1. Field of the Invention
This invention relates to the field of large-diameter fiberglass-reinforced synthetic resin tanks which have diameters in the range of about 8 to about 60 feet and are capable of holding thousands of gallons of corrosive chemicals, etc.
2. Description of Prior Art
In my prior U.S. Pat. No. 3,956,816, there is shown and described a method of oblating, nesting, transporting, and erecting fiberglass-reinforced tank sections, making it practical to erect very large tanks at great distances from a factory where the tank sections were constructed. The joints described in said patent were made entirely by hand lay-up and required much time and labor. In this connection it is emphasized that each joint must absolutely seal the liquid contents of the tank, which contents may be highly corrosive and under very substantial pressure. Furthermore, the joints must create sufficient axial strength and (in some cases) hoop strength at the abutted tank section ends to withstand the stresses created during the erection process and also the stresses caused by the stored liquid in the tank.
When hand lay-up of fiberglass cloth impregnated with synthetic bonding resin is the only means employed to form such joints, factors such as irregularities in the exact shapes and sizes of the sections become relatively unimportant. However, it is emphasized that (as stated) such hand lay-up is a highly laborious operation requiring much skilled labor. To supplant all or part of the hand lay-up method by a method which requires greatly less labor and also improves the quality of the tank, it is necessary to overcome the major problems created by the above-indicated irregularities in shapes and sizes. In this connection it is emphasized that when tank sections are (for example) 40 feet in diameter, it becomes impractical or impossible to achieve perfect abutment, perfect cylindrical shapes, etc., so that irregularities necessarily result.
Referring next to prior art other than applicant's own patent, it has been well known for many decades that joints between the ends of pipe sections, the components of small tanks or containers, etc., may be made by injection of bonding material into annular chambers defined at the joints. However, relative to these small-diameter and substantially rigid elements, there exists none of the major problems which have been overcome by applicant, and there is no suggestion that such problems may be overcome--with surprisingly beneficial results--as has been accomplished by applicant.